1.Very carefully clean the clams and the mussels (after scraping the mussels with a brush) and rinse them several times under running water to remove all impurities

2. Put the mussels and clams in a pan with one tablespoon of olive oil, cover the pan and heat over medium heat, “shaking” the pan by the handle every so often to mix the shellfish and jerking the pan with rapid movements with your wrist to thoroughly mix the contents

3. Cook until the mussels and the clams open

4. Remove from heat and let cool

5. Once cool, remove the clams and mussels from their shells and put them in a bowl

6. Strain the broth from the clams and mussels through a fine-mesh sieve and gently transfer it to a separate container

7. Heat the remaining oil in a fairly large pan over medium heat and add a generous tablespoon of chopped parsley, the sage leaf and immediately afterward the cleaned and chopped squid

8. Let brown slowly for a few minutes, then add the white wine

9. Allow the liquid to evaporate completely and then add the crushed tomatoes

10. Cook the sauce for 5 minutes and gradually add 3 or 4 tablespoons of the strained water in which the mussels and clams were cooked

11. Cover the pan and cook for 6-8 minutes

12. During the last 3 minutes of cooking add the mussels, the shelled clams and the peeled and deveined shrimp

13. Meanwhile, cook the Spaghetti in a large quantity of boiling water for the time indicated on the package